Over fueling or lack of fuel

[Whitecat90]

i have a 90 tsi awd talon. i just rebuilt the engine and installed a bunch of new stuff. I have 780cc pte injectors, walbro 255hp fuel pump that it hot wired, i only have stock fuel lines and fuel rail. im running a second gen maf and a stage three chip from dsm chips made for the setup at 43 psi. If u turn over teh car with the fuse in for the relay then it puts to much fuel in and it wont start. if u take the fuse out itll start to run and idle and u can shove the fuse back in and sometimes itll idle. but only will do that at 25-30 psi. im not sure what could be making this happen or why. Any info from u guys would be great. thanks

 

[rlacasse1]

Are you still running the stock Fuel Pressure Regulator? If you are, the 255 may be over running it. Not to many people have had much luck using the stock FPR with a 255.

Also, do you have any idea what your base fuel pressure is?

 

[Whitecat90]

sorry about the double post my computer froze in the middle of posting it.

and yes i do have an adjustable reg. thats how we got it to run we turned it way down and when it would finally start it was at 25-30 psi on the gauge.

but even with it that low the car will sit and idle. and the one time i did try to move it it died as soon as i started to let the clutch out.

 

[rlacasse1]

You should have the pressure set at 37 PSI with the car running and the vacuum line disconnected.

See this thread for more info.

http://www.dsmtuners.com/forums/newbie-forum/397498-fuel-pressure-questions.html

And this thread.

http://www.dsmtuners.com/forums/newbie-forum/359811-1g-base-fuel-pressure.html

 

[Whitecat90]

ok thanks ill try that and take a look at the other threads u linked.

 

[rlacasse1]

Have fun. Just try that and report back and let us know where you get with that.

And if that doesn't fix it, we will move onto the next thing.

Oh, another question. Have you tried running it with the stock 1g maf?

 

[Whitecat90]

no i havent. i havent run the 1g maf since i bought the car casue it came with the second gen maf already installed and with a chip setup for it already

 

[garner]

Could be the maf and chip messing it up. Try what rl suggested and then try the maf and chip

 

[Whitecat90]

Well ive never had problems with the maf on the car but the car has sat for over a year while ive been rebuilding it. So if the fuel pressure doesnt fix it should i swap back to the other chip and smaller injectors and see what happens?

 

[Whitecat90]

UPDATE: i set fuel pressure last night and the car started right up. It still has problems idleing and restarting after it gets shut off. I also noticed it has very low vaccum at idle. Around 10 in hg. I am going to put a timing light on it and recheck the timing belt.

 

[TuRBoTaLooN]

Two things:

1) Sounds like you have a boost or vacuum leak based on the vacuum at idle. But you should also make sure your throttle plate is 100% closed at idle. That will obviously affect your vacuum. Do a boost leak test and report back.

2) You said the chip was set for 43psi? That doesn't provide any useful information. What injectors was it programmed for and what MAF? If the chip is set for 450cc injectors and you're using 780cc injectors, then the ecu is simply pumping too much fuel into the cylinder. Think of it this way, if (for example) the ecu needs to open the injector 20% at startup, on a stock injector thats (20% * 450cc = ) 90cc per cylinder. If you just throw in a 780cc injector, that nets you 156cc! That is almost twice as much fuel! Please provide as much information as you can regarding the chip.

Also, if you have the ability to log any information, especially AFR from a wideband, please do so. Things like IDC (injector duty cycle), fuel trims, TPS position, etc could be very useful to diagnose.

 

[Whitecat90]

Ok well the chip is a stage three from dsm chips. Its setup for 780cc injectors, 2g maf, 800 rpm idle and 43 psi of fuel pressure. Ill do a boost leak test today along with the other stuff i mentioned before and ill check the adjustment on the throttle cable.

And im not sure if i mentioned it before but every plug in the car is pitch black.

bump for any thoughts. the weather prevented me from getting any work done tonight so i will pick up tomorrow

 

[Whitecat90]

UPDATE: i found out that the cam timing was off. When i tried to check ignition timing the car would shut down and not what to restart. So i pulled the top cam cover off and set it at tdc and found that the timing belt was off by two teeth. I re did that and the car fired right up and is running great. Only problem i seam to have now is that the tach wont work and im not sure why.